Using VBR mode (-q) will give the best quality. The default setting is -q 0.5, which will give about 160-170kbps on average. For ABR, use the -br options. For CBR, use -cbr. Note that the bitrate is in bits per second, not kilobits.

Note that using 2-pass encoding makes no sense in VBR mode!

When encoding from the commandline, sending the input over stdin is supported, but then you should also use -ignorelength. This is not needed when using temporary files.

don't forget to include at least one blank space character before your first argument,

The "[InFile]" and "[OutFile]", as written above, are not variables looking for a substitution. With dBPowerAmp, you literally write them in just like that, as they appear above, with the square brackets.